1. Field of the Invention
The invention is based on a quick-action flap in accordance with the preamble to claim 1.
2. Discussion of Background
Such quick-action flaps are provided, for example, for the rapid interruption of the steam supply to a turbine of a power station installation. Quick-action flaps of conventional type are known which have housing bodies which are complicated to manufacture. These housing bodies are subjected to comparatively high temperatures.
From the publication EP-A1-0 374 644, a quick-action flap with a flap plate is known which has a housing body with a service opening let into it. The flap plate is fastened to a driven shaft. Two bearing positions, in which the shaft is supported, are machined into the housing body. A seating ring which interacts with the flap plate is let into the housing body so that, when required, the flow of steam through the quick-action flap is interrupted by the flap plate being in contact with the seating ring. In this embodiment, the bearing positions are arranged near the service opening, i.e. in a region of the housing body where the stress distribution is problematic.
Such quick-action flaps must operate very reliably in all operating situations in order to satisfy the high requirements made with respect to operational reliability and dynamics. A quick-action flap of this type is not suitable for higher temperatures because deformation of the housing body cannot then be excluded. If, however, the housing body should distort due to excessive heating and pressure loading, the shaft can jam in the bearing positions so that the flap plate moves too slowly or not at all.